Venetian blind ladder webbing



March l, I1955 G. F. FRENCH ETAL VENETIAN BLIND LADDER WEBBING 4 Shee'ts-Sheet l Filed May 24, 1952 March 1, 1955 G. F. FRENCH ETAL VENETIAN BLIND LADDER WEBBING 4 sheets-sheet 2.

Filed May 24, 1952 March 1, 1955 G. F. FRENCH FAI..

VENETIAN BLIND LADDER WEBBINGl 4 Sheets-Sheet 3 Filed May 24,` 1952 March l, 1955r G. F. FRENCH ETAL l2,703,113

VENETIAN BLIND LADDER WEDDING Filed May 24, 1952 4 Sheets-Sheet 4 Inventors GEORGE FREDRICK FRENCH MATTHIAS STEPHENSON JOSEPH ANDREW MCGLYNN Attorneys United States Patent() VENETIAN BLIND LADDER WEBBING George Frederick French, AHale, Matthias Stephenson,

Sale, and JosephAndrew McGlynn, Manchester, England; said Stephenson and sad.McGlynn assgnors to said French Application May 24, 1952,`Serial No. `289,844

Claims priority, application Great'Britain May 25, 1951 16 Claims. (Cl. 139-384) This invention relates to Venetian blind ladder webbing and the like, that is to say, webbing of the kind used mainly for carryingthe slats ofa Venetian blind and consisting of two outer webs, usually termed the body webs or bandings, which are connected together at intervals by a plurality of cross strapsformed` from warp threads which are bound into the two body webs alternately, that is to say in which each set of cross strap warp threads is bound in first into one body web and then after a short cross-over (subsequently to be severed) into the other body web followed by a longy cross-over of free warp ends to form a cross strap before binding-in again to the rst body web. Where thev cross straps are woven this weaving iseiected simultaneously during the weaving of the main body webs. The short cross-over portions of the warp threads are subsequently severed to allow the main webs to separate into the characteristic ladder-like form, from which'this kind of webbing has acquired its name. While the invention is particularly applicable to ladder web having woven cross straps it is also applicable to` ladder web in which the cross strap warp threads are n'ot woven.

There are many known forms of ladder webbing of the kind above referred to and in particular one` of the main problems which the manufacturer hasmet has been to ensure security of the cross straps so thattheir warps, after cutting at the short crossover as aforesaid, are not readily pulled out from the positions where they are bound into the main body web. This problem is more acute with the smaller gauge or closer spacing of the cross straps than with the largergauges, as the possible fi length of the binding-in area varies mproportionr to the spacing of thecross straps.

In order to ensure security of binding-iu ithas hither to been considered necessary to weave with a relatively close weave, such as 34 picks perinch of 2 ply` yarn and '1 to have say 16 to 20 picks at eachl endof the cross strap where the warps are bound to the body web. Consequently the whole length of the webbing must be closely woven.

1n order further to obtain better security for the binding-in, it has been proposed at each binding-in, to interchange all of the cross strap warp threads with an equal number of body warp threads so` that all the cross strap threads are bound in at each end for at least the distance between consecutive cross straps. During such binding-in the warp threads of one set displaced from the body webs form a cross strap intermediate of those formed from another set of Warp threads. The method of binding-inl in which a cross strap warp thread (which term is used to include a set of warp; threads) is woven with the body web intermediate of the formation of a cross strap by another warp thread, will .be hereinafter termed long binding-in. In such manner of weaving aforesaid, it is necessary to be able to provide selectively four stages of lift for each of the cross strap shafts so that the cross strap warps may be shed along with the body warps of each body web, and this has required at least three dobby jacks per shaft. Also, as all the warps of any one cross strap have to be in each body web for at least the length of a cross strap and as overlap must be provided for the slats of the blind this means that such warps can only form every third cross strap, so that six shafts are required for each line of cross straps.

Assuming therefore one ,isconsidering Ithe usual type of ladder web in which :there are two parallel sets of CFI 2,703,113 Patented Mar. 1, 1955 ice cross straps in staggered relation, one would require at least 36 jacks operating l2 shafts for the weaving and binding-in of the cross straps alone. The shafts for the body webs, usually four with double-eyed healds one eye for each web, could be Worked in normal manner off cams and tappets (i. e. separately from the dobby) for twill weave. Such webbing has never been produced on a commercial scale, except with unwoven cross straps, and using only two shuttles and so that only twelve jacks were required. Therefore, only one shuttle has been available at each binding-in, as compared with the method also known of using the cross strap shuttles as Well as the main web shuttles at each binding-in to make a 2-ply fabric with the warps interlocked by the wefts, and thus the security only of a simple binding has been obtainable when providing the long binding-in. This factor again compels the manufacturer to produce a relatively closely woven fabric in order to ensure security at the binding-in .points of the woven straps after cutting, in spite of the long binding-in.

The object of the present invention is to enable the production of webbing of the kind referred to in which a relatively open or light picked weave may be adopted while obtaining ample.` security for the binding-in, and a further object of the invention is to enable the production to be speeded up. A still further object of the invention is to enable the cross straus to be woven without the shedding complication above described.

According to the invention, ladder webbing consisting of two outer webs connected together at intervals by a plurality of cross straps formed from warp threads which are bound into the two body webs alternately, that is to say in which the warps forming each cross strap are bound rst into one outer web and then after a short cross-over, subsequently to be severed, into the other body web followed by a long cross-over forming the cross strap before binding again into the rst main web, is characterised in that each cross strap is formed of at least two sets of warp threads which cross over at different short cross-over positions so that at each end of the cross strap one set at least of the warp threads crosses over immediately after binding-in while another set of warp` threads at least continues to be woven with the main web. Preferably such weaving with the main web is continued until such warp threads are required to cross over to Vcombine again with the other warp threads for thek commencement of another cross strap.

In one example of the invention a narrow fabric loom having four shuttles for each piece is set up with twelve shafts, four of which are arranged for actuation of the outer bands or body webs by tappets in known manner.

The remaining eight shafts are each connected to eight 'having one .end anchored and the other end connected to the other jack. Thus one quarter of the movement of the last named jack is transmitted to the shaft, one half of the movement of the first named jack is transmitted to the shaft or a movement is obtained when both jacks are simultaneously actuated.

As regards warps, there are 80 ends for each body web which are divided in known manner to the four tappet-actuated double eyed shafts, which warps always remain in their respective body webs and ll cross strap warp ends in each of the remaining 8 shafts.

In operation, the warps are shed so as to produce a ladder web of the known type having two body Webs woven in twill and two lines of plain woven cross straps in parallel but symmetrically staggered relation. It is therefore convenient to consider one line of cross straps only requiring 4 shafts. During the weaving of one cross strap, two of the said 4 cross strap shafts are shed for plain Weaving by one of the inner shuttles while `one of the said 4 cross strap shafts is shed simultaneously with the twill-shedding of the tappet-actuated shafts but in plain weave, whilst the other is shed in the oppo site web. The use of plain weave for these cross strap warps gives them extra security in the body web. Thus only 4 shafts and 8 jacks are required for the shedding and binding-in of the cross strap warp threads for one line of cross straps. Obviously the other 4 shafts and 8 jacks are similarly used for the other line of cross straps.

In the accompanying drawings:

Fig. 1 is a weaving diagram showing the shedding for say Nos. 4 and 3 shafts carrying the warp threads for certain cross straps;

Fig. 2 is a synchronous diagram showing the shedding for say Nos. 2 and 1 shafts for the intermediate cross straps in the same line;

Fig. 3 shows Figs. l and 2 superimposed;

Figs. 4, 5 and 6 are similar diagrams showing shedding for an alternative method of binding in;

Fig. 7 is a perspective View of the ladder webbing produced by the weaving diagrams 1 to 6 above; and

Fig. 8 is a diagrammatic sectional elevation of a ladder webbing woven in accordance with the weaving diagrams of either Figs. 1, 2 and 3 or Figs. 4, 5 and 6.

In all the above diagrams the warps for the main body web are omitted for the sake of clarity.

The diagrams are of conventional form in which the wefts A, B, C and D for the shuttles are shown as lines of dots and the warps as lines interwoven therewith. Thus in Fig. 3, the warp h of No. 4 shaft is shown in full line, that g of No. 3 shaft in dotted line, that f of No. 2 shaft in single dot chain line, and that e of No. l shaft in double dot chain line.

As can be seen from the drawings, the warp threads of 3 of the cross tape shafts take part in the binding-in into each body web. That is to say the warps e, h and g are shed for weaving by the wefts A and B of two lower shuttles during binding-in of the cross strap formed by h and g between the points w-w and x-x; and the warps e, f and h are shed for weaving by the wefts B and D between the points x-x and y--y. The weft C is meanwhile being used to Weave across strap of the other line and as the warps f and h are shed relative thereto as to pairs of picks or an even multiple, the weft C does not weave with them. As can also be seen from Fig. 3 especially, the cross strap separately formed to the left of the line w--w by the warps h and g and the weft B, ceases its identity of the line w-w, the warps h and g being tightly bound into the lower body web along with the warp e between the lines w-w and x-x but to the right of the line x-x such warp g moves to shed only for weaving by the weft A in the lower body web. Between the lines x-x and y-y, the warp f is shed with the warps h and e for weaving by the wefts D and B. To the right of the line y-y, the warp h continues to be shed only for weaving by the weft D while the warps f and e are shed for weaving only with the weft B to make the intermediate cross straps of the line. At the next binding-in the charts are exactly the same as Figs. l, 2 and 3 with the warps and g substituted for the warps h and e respectively and vice-versa. The short cross-over portions occur at the point indicated by the arrows in Fig. 3 where the warps h and e are ultimately cut so that the main webs may be drawn apart while connected by the cross straps in the manner of rungs of a ladder. In consequence of the above arrangement it can be seen that the warps e and g carried by the odd numbered shafts never shed with the top shuttle and the warps f and h carried by the even numbered shafts never shed with the bottom shuttle. The same applies to the other 4 shafts.

The charts shown in Figs. 4, 5 and 6 show a slightly different order of shedding which however results in relatively weak points of binding-in at the locations 1, 2, 3, 4 and 5 as indicated. The charts will not be described herein in detail as they will be obvious after study of the preceding gures and to anyone familiar with the art. The warps and the cutting point are indicated in the same manner as in the earlier figures.

As previously stated, the warps of the main body webs carried by the tappet-actuated shafts are not shown but are shed for a twill weave all the time.

By reason of the new arrangement of shedding in which the warps forming the cross straps divide into the two body webs at each binding-in, it is possible to have alternate cross straps from the same warps, thus reducing the number of shafts required from 12 to 8 and ensuring the strong binding-in and continuity at opposite ends of each cross strap of one of the warps for the whole length of a cross strap as well as for the length of the binding-in, gives sulicient security to enable a lighter pick to be used, thus increasing the rate of production. Also, the invention makes possible an arrangement of shedding movements imposing less stress on the loom and therefore enabling the looms to be further speeded up while working more smoothly than was possible with the earlier construction of webbing aforesaid. The ladder web itself has also new characteristics of symmetry with inherent advantages.

Where the invention is applied to ladder web in which the cross straps are not to be woven, only two shuttles would be required but in consequence also only one shuttle is available at each binding-in. In order therefore to obtain the same security of binding-in for the cross strap warp ends a heavier or closer pick would be required through-out the whole length of the webbing but the shedding simplicity of the invention still obtains. However, the warp ends during each long binding-in are in every case shed for weaving, whether in plain or twill, with body warp threads, and consequently such body warp threads give additional security for binding-in of the strap warps, and therefore it is still possible to use a relatively light weight of pick compared with previously known ladder web.

It is also obvious that the body web could be shed in plain weave instead of in twill as in the example described and this would still further strengthen the binding-in and the webbing as a whole, but the general appearance is less attractive and the additional strength thereby gained would not generally Warrant the change.

Fig. 7 shows diagrammatically ladder webbing made in accordance with the weaving charts described earlier. It is not possible in such gure to show at the same time the dilferent sets of warps and the actual result of the different methods of binding-in. Consequently this figure is conned to showing only the warp threads and their relative positions for one row of cross straps, the relatively intermediate cross straps of the other row being shown in outline only. The reference characters for the cross strap warp threads agree with those in the weaving charts, two warps only of each set being shown for clarity. It is to be assumed, though it can only be shown in small areas, that the main webs are woven with weft A and D and the cross straps with weft B and C as indicated.

Referring now to Fig. 8, there is illustrated diagrammatically a sectional elevation of a ladder webbing woven in accordance with the heretofore described weaving diagrams prior to cutting of the short cross overs. As shown in this figure, the warp threads are shown straight and not undulated and it must be assumed that threads lying parallel to each other are woven by wefts not shown but as indicated in the other diagrams, the exception being at the vertical portions which represent the short cross over between bindings-in to the main webs and where such threads have to be cut as indicated by the arrows. The next consecutive binding-in areas corresponding to those between the lines w, x and y are shown between lines w', x', and y in order to give a repeat and to show the short cross over of the warps f and g corresponding to that of e and h and to show that alternate cross straps are formed of the warps e, f and g, h respectively. The warp threads e, f, g and h which are used in pairs e, f and g, h, to make the cross straps are shown in the same form as in the weaving diagrams. In addition to these warps there are of course other warps making the main webs and these are indicated in this ligure as z', a line through a row of single circles, and as j, a line through pairs of circles. The warps f and h are alternately (when not in cross straps) woven with i between the binding-in areas, while similarly e and g are alternately (when not in cross straps) woven with i.

The strength of the binding-in for the cross straps is mainly due to the fact that, considering for example the top end of the cross strap formed of the warps e and f, although the warp e is severed at short cross over x, the warp f extends to the left as far as the next short cross over corresponding to x' and similarly at the lower end of the cross strap, although the warp f is severed at short cross over x' the warp e extends to the right as far as the next short cross over corresponding to x. Consequently at each end of the cross strap, half the cross strap warps continue beyond the bindingin, so as to be woven in the main web and through the next binding-in to the next followingv short cross over.

This ensures ample strength to prevent the warps of the cross straps from being pulled out. So as to avoid confusion the warps i and j are not shown at the bindings-in where there are already three warps, but it is to be assumed that these warps continue through such zones.

It is to be understood that the invention is not limited to all the details of the example above described as obviously some modifications already well known in connection with ladder webbing, may be embodied in the construction by way of modification without prejudice to the fundamental characteristic of the present invention. For example, intermediate and longitudinally overlapping cross straps could be introduced in each row, which would consist of additional warp members arranged in accordance with the characteristic of the present invention and these additional cross straps could be weftless or partly woven while the cross straps of the example illustrated could be part woven or even weftless if desired, though the presence of weft in the cross straps does operate to ensure distribution of load to both sets of warps forming each cross strap.

What We claim is:

1. Woven ladder webbing consisting of` two woven outer webs, a plurality of cross straps connecting said outer webs together at intervals and each consisting of lengths of warp threads having their ends woven into the said outer webs characterized in that at each end of each cross strap some of the warp thread ends are short while other ends of concurrent warp threads are long, with the cross straps and their ends in line so that when the webbing is flat the termination of the said short warp ends in one outer web is coincidental with the commencement of short Warp ends in the other outer web of another cross strap while the concurrent long web ends of each cross strap continue in the outer web beyond the short warp ends of such cross strap and terminate coincidentally with the short warp ends in the same outer web of a succeeding cross strap.

2. Woven ladder webbing according to claim 1 further characterized in that the long warp ends are coterminous with the short Warp ends of the cross strap commenced in the other outer web with the termination of the concurrent short warp ends.

3. Woven ladder webbing according to claim 1 in which the cross straps include weft threads.

4. The method of weaving ladder webbing consisting of two woven outer bands connected together at intervals by a plurality of cross straps wherein warp threads for the cross straps are woven into one outer band to form the end of one cross strap and then taken across and woven into the other main band to form the commencement of another cross strap including the step wherein after each such weaving-in some only of the warp threads of the cross strap are taken across to the other main web to commence the new cross strap while other warp threads of such first cross strap are woven for a further distance into the first main web before being taken across and Woven into such other main web to form part of the warp threads of the commencement of a further succeeding cross strap.

5. The method of weaving latter web according to claim 4 wherein the cross strap warp threads which are retained in the weaving of the first main web are carried `across for weaving into the other main web immediately after the binding in to the said rst main web of the other end of the cross str-ap commenced with the preceding carrying across of some of the warp threads of the tirst cross strap.

6. Woven ladder webbing comprising two woven outer bands and a plurality of aligned cross straps therebetween, said cross straps including a plurality of warp threads and at each end of each cross strap some of said warp threads thereof being woven into one outer band for a distance substantially shorter than the distance be tween successive aligned cross straps and others of said warp threads being woven into said one outer band for a distance equal at leas-t to the distance between successive aligned cross straps.

7. Woven ladder webbing according to claim 6 in which the warp threads that are woven into an outer band for the substantially shorter distance terminate in said outer band.

8. Woven ladder webbing according to claim 6 in which the warp threads that are woven into one outer band for the substantially shorter distance at one end of each cross strap are woven into the other outer band at the other end of the cross strap for a distance equal at least to the distance between successive aligned cross straps.

9. Woven ladder webbing according to claim 8 in which the warp threads that are woven into an outer band for the substantially shorter distance terminate in said outer band.

l0. Woven ladder webbing according to claim 8 in which the cross straps include weft threads.

11. Woven ladder webbing comprising rtwo woven outer .bands and a plurali-ty of sets of warp threads passi-ng back and forth therebetween to form a plurality of aligned cross straps extending between said bands and a plurality of Crossovers extending between said bands, said cross straps an-d said cross-overs alternating throughout the length of the ladder webbing and each including at least two sets of warp threads, at each end of each cross strap one of said sets of warp threads thereof being woven into one outer band for a distance subs-tantially shorter than the distance between successive aligned cross strap-s and the other set of warp threads thereof being woven into said one outer band for a distance greater than the distance between successive aligned cross straps, and one set of warp threads in each cross-over being one of the two set-s making up the immediately preceding cross strap and the other set of warp threads or' said cross-over being one of the two sets of warp threads making up the second preceding cross strap.

l2. A method of making ladder webbing having a pair of woven outer bands and a plurality of aligned cross straps bound in at their opposite ends to said outer bands and each including a plurality of sets of warp threads, which comprises weaving each set of warp threads rst into one outer band, then carrying said set over to the other outer band to form part of a cross str-ap, weaving said set of warp threads into said other outer b-and for a short distance, crossing said set of warp threads back over to said one outer band to form part of a cross-over and weaving said set into said one outer band for a substantialdistance at least as great as the desired distance between tW-o successive cross straps, and again carrying said set of warp threads over to said other outer band to form part of another cross strap.

l13. A method of making ladder webbing according to claim 12 in which, with each set of warp threads that is crossed over from said other outer band to said one outer band to form a part of a cross-over after being woven into said other outer band for a short distance, vanother set of warp threads is crossed over from said vother outer band Ito said one outer band, said latter set of warp threads being a set that has just been woven into said other outer band for a distance greater than the desired distance between two successive cross straps.

l14. A method of making ladder webbing according to c1aim l2 in which at least one of said sets of warp threads formlng each cross strap is woven for the substantial r11-stance in one outer band and another set of warp threads forming said cross strap is woven for the substantial distance into said other outer band.

I1.5. A method of making ladder webbing according to 4claim 14 which includes the step of weaving weft threads into each cross strap a-s the latter is formed.

lr6. A method of making ladder webbing according to claim 14 which includes the step of cutting the crossovers.

References Cited in the le of this patent UNITED STATES PATENTS Re. 22,925 Rasero Oct. 7, 1947 2,141,038 French Dec. 20, 1938 2,609,012 French et al. Sept. 2, 1952 

